Electrode suspension



March 9, 1937. R TQRCHET 2,073,356

ELECTRODE SUSPENS I ON Filed April 18, 1935 Patented Mar. 9, 1937 UNITED STATES PIATENT OFFICE ELECTRODE SUSPENSION n Pierre Torchet; Riouperoux, Norske Aktieselskab Det Industrl, Oslo, Norway ApplibflfiOll April 18,193 Serial No. 666,76 8 Claims. (01. 13-15) The present inventionielates to the so-called I Siiderberg electrodes which are baked while in use in the electric furnace and consist of a baked and an unbaked part. One object of the invention is a new and improved form of such electrodes for use in the electrolytic production of aluminum.

Ordinarily the Siiderberg electrode is provided with a metalcasing acting as a mould. The

the gas bubbles which form under a round electrode of a certain cross section tend to become considerably larger than underneath an oblong electrode, in correspondence with the smaller circumference. A round electrode also has a tendency to become overheated in its center por- -tion, whereas with oblong electrodes of restricted widths there is less risk of overheating of the is important to .avoid any overheating of the central part of the electrode.

ng operation the surface of .the melted aluminum metal in the pot is not horizontal, but

seems to be moving all the time showing a considerable difference in level at various parts of the pot. A difierence one-half inch has of which is not entirely clear. be caused by electro-magnetic ing the distance France, assignor to for Elektrokemisk in a rapid circulation of the metal. The applicant believes, however, that the more important cause of the waves is the escaping gas bubbles. At least the fact remains that the waves exist and I that the same are important in the operation of 5 the pot. It is easy to understand that suchwaves are formed very readily owing to the extremely small difl'erence in specific gravities of the fluid aluminum and the fluoride bath from which the 20 During the electrolysis the voltage of the aluminum pots is ordinarily kept between 4 -7 volts per not In order to have a good output of metal per kw. it is necessary to operate at the lowest possible voltage. it is only possible to lower' the voltage by reduclower end of the good. This distance, however, is determined by the height of the waves 3 in the metal. The waves-inthe surface of the aluminum therefore determine to'a large extent the operating voltage of the pot. It-is therefore important to this been found that a minimum anodetance may be maintained even for size pots whereby I improved and no overheating will take place. Thereby it has been rendered possible to build 55 cathode disthe largest the operating voltage will be Other conditions being equal 26 2 pots of much increased size. The applicant has used 60,000 amperes on a single pot and is convinced that still much larger pots are possible in this way. These oblong electrodes of restricted widths are ordinarily rectangular but it will be understood that any oblong electrodes having the dimensions above referred to, are useful.

The suspension of these'oblong electrodes in volves certaindifliculties which applicant has solved in a very serviceable way.- It is necessary not only to suspend the electrode'securely and to allow it to be lowered little by little into the pot as it wears off at the lower end'but also to reinforce the electrode .so that it will not become deformed during operation owing to the hydrostatic pressure from the soft paste in the upper part of the electrode. A further object of the invention is, therefore, a suitable electrode holder for use in connection with these oblong electrodes. The electrode holder herein illustrated consists of a steel structure arranged in connection with contact studs which extend into the electrode at least fromtwo opposing sides. These 'contact studs have previously been described in U. S. Patent No.

1,757,695. When the studs have been securely baked into the electrode they are very firmly connected with the baked part of the electrode, and offer an excellent means for suspension. However, as the: electrode wears off the steel structure approaches the top of the fluid bath and it is necessary to remove the lowest part of the structure as well as the lowest set of studs, and to arrange the holder for suspension of the electrode from the set of studs next higher up. Before the suspension is changed however, it is necessary to make sure that the set of contact studs next higher up has been securely baked into the electrode, 40 for whichv reason the electric current should .be passed through these studs for a certain length of time before the suspension is changed and the lowest suspending structure is removed. Further objects of the invention will appear as the specification progresses.

The accompanying drawing which forms a part of this application is schematic and illustrates one suitable form of the invention. No limitation on the invention is to be deduced there- 50 from.

In the drawing Figure 1 is a longitudinal elevation, partly broken away in vertical section, illustrating the invention as applied to an aluminum furnace in which two rectangular elec- 55 trodes are employed;

Fig. 2 is a front elevation, partly broken away in vertical section, of the furnace and apparatus of Fig. 1, illustrating primarily the electrode holder,-its suspending means, the contact studs 60 and their connection with the source 'of current;

Fig. 3 is a. fragmental view, partly in vertical section, illustrating primarily secondary supporting means for the electrode holder shown in Fig. 1;

Figs. 4 means employed in assembling and locking the electrode holder of Fig. 1. r

The arrangement illustrated in'Fig. 1 is of an aluminum pot with two Soderberg electrodes 70 of restricted widths acting as anodes. The arrangement of two electrodes in one pot has the advantage that the part of the bath which is between the two electrodes stays very fluid so that the crust on top of the same is thin and 75 can be broken up more easily than at the outelectrodes, leaving lengthwise and centrally as at locked by means of supporting bolts 1-1, one

and 5 are detail views illustrating side of the electrodes. It is even possible to operate at the pots in such a way as to work regularly only the part of the-pot between thetwo the crust around the electrodes until the pot is tapped, when it should be broken up owing to the change in level of the bath during tapping.

The furnace i has mounted thereon a superstructure comprising upright beams l5-l5 to which are attached at the top cross-beams I4'-l4', which in turn support two beams i i-l4 lying lengthwise of the furnace, one on each side of the electrodes 2-2.

The electrodes 2, of which two are illustrated, are of the Soderbei'g self-baking continuous type as heretofore referred to, are rectangular in cross section and are provided with a metallic casing 2'. Each of the electrodes is provided on two opposite sides with rows of metallic conductive contact studs 3-;3. These studs are preferably arranged in rows in step formation as illustrated in Fig. 1, the rows, of which four are shown, being approximately six to twelve inches apart. The.

studs extend through the metallic casing of the electrodes into the interior thereof a suflicient distance to assure effective baking and heating of the electrode and to afiord a rigid means for supporting the electrode in cooperation with the electrode holder. They project laterally from the electrode through the electrode holder and extend a suflicient distance therefrom for ready connection with the current supplying means.

Two bus bars l6-l6 are suitably supported, one on each side of the electrodes, on the furnace superstructure above described. These lie longitudinally of the furnace and are preferably located about even with the top of the electrode holder. A plurality of copper bars 4--4, one set for each side of the electrodes, are suitably connected with the contact studs. As illustrated, these bars are vertically positioned and each connects in parallel the studs on its respective side of the electrode which are correspondingly placed in vertical line -as shown" two studs for each bar of which ordinarily only the lower is attached to the bar, the upper stud beinghowever, also attached for a time just before the suspension 1 is changed to insure that it is securely baked into the electrode. Flexible cables 5-5 by suitable connections electrically connect the copper bars 4-4 with their respective cooperating bus bars lG-IG.

The electrode holder comprises alternately stacked beams 6-6, preferably made of iron and each consisting of two channel irons assembled as illustrated in Fig. 4. These beams overlap at their ends and completely surround the electrode. The beams at their overlapping ends are slotted I8 and are interfor' each corner of the holder, which bolts are positioned in the slots slots being slightly wider than the bolts so that the bolts pass freely therethrough. These bolts at their bottoms bear. circumferential grooves I for cooperation with key pieces 8-8, which are slotted at one end lengthwise and centrally as illustrated in Figs. 4 and 5, the width of the slots being substantially the same as the diameter of the grooved portion of the bolts. These keys are removable, and the structure as a whole is such that the lowest pair of beams of each holder may be removed as the electrode burns away on the end and the bolts attached as above described to the pair of l8 just mentioned, the

beams next higher up;

The bolts 1-1 are each attached to cables 9-9, but insulated therefrom, which cables by suitable pulleys extend to and are operated'by winches Ill-l of ordinary construction mounted upon the furnace superstructure above described, all in a manner which will be readily understood.

The electrode holder in the structure illustrated mechanically cooperates with the contact studs 3-3 in suspending the electrode. The lowest pair of the beams 6-6 on the sides of the electrode in which the studs are embedded are placed immediately beneath the lowest row of studs, so that this pair of' beams supports the electrode from these contact studs. The contact studs in the rows above, prior to the transfer of the suspension thereto as above indicated, preferably carry no weight and are so positioned that theelectrode holder in no way disturbs their initial embedding in the electrode mass electrode is made.

During the removal of the lowest beams of the electrode holder and the attachment of the bolts 1-1 to the beams next above on the sides of the electrode in which the contact studs are embedded, it is necessary to support the electrode and the holder by other means than the bolts themselves, and secondary suspending means are herein illustrated for that purpose. These secondary suspending means comprise hooks Il-ll suspended on chains I2-l2 which are connected with hooked rods iii-l9 by turn buckles Iii-l3. The hooked rods iii-l9 are suitably suspended as from the lengthwise beams l 4-1 4 of the furnace superstructure heretofore referred to. These beams rest with their ends on the cross beams |4-l4. The holder beams may be suitably apertured to offeradequate engagement for the hooks l-ll therewith during the-employment of the hooks in supporting the electrode and its holder, as illustrated in Fig. 3.

In operating a furnace equipped as above, the electrodes are raised or lowered to the desired position in the furnace as heretofore indicated and the desired distance between the aluminum metal on the furnace bottom and the electrodes maintained by means of the winches Ill-l0, which are preferably operated simultaneously to maintain an even distribution of the current through the two electrodes. When the bottom portions of the electrodes are burned away in use so that the lowest pairs of beams on the electrodes would be brought too close to the melt, the hooks H-ll of the secondary suspending means are engaged with the pair of holder beams next above, and the lowest beams are removed, the key pieces 8-8 being withdrawn for thispurpose. At-this time also, it is desirable to remove the lowest rows of contact studs 3-3 unless they be made of such metal as would not contaminate the melt.

While the hooks ll-ll of the secondary suspending means are thus engaged, it would be obvious-that the electrode and its holder will be supported from the row of contact studs next above those originally supporting the holder. After the removal of the parts just indicated, the holder 'bolts 1-1 are raised by means of 'the winches until their flange portions 1-1' are brought into proper position in respect to the pair of beams which now become the lowest beams of the holder, for cooperation with the key pieces 8-8, the key pieces are then inserted, and interlocking of the beams effected as will be readily understood. The secondary suspending hooks ll-Il are then disengaged and the control of broadly in of which the the electrode and its holder resumed by the winches Ill-l0.

As the lowest beams are removed, the holder is built up at the top by connecting in with the bolts 1-1 the beams removed from the bottom or like beams, referred to comprehensively and the claims hereof as similar parts or beams. The slotsAB in v the ends of the beams permit the latter to be slightly tilted and inserted between the bolts, and then dropped down into horizontal positionin engagement with the bolts at the top of the stack without disturbing'the bolts or their connection with the stack. In this way the structure of the holder is maintained. At the same time also contact studs similar to those removed from the bottom are embedded above in the unbaked portion of the electrode in the row formation above described, and the copper bars 4-4 are raised and connected into the studs above those originally connected.

When the copper bars 4-4 are being raised the electric current cannot flow through the disconnected stud but the other studsof the electrodes will maintain the supply of current so that the electrodes can operate altogether continuously all through the transformation of the holder.

The above example is given for illustrative purposes only and all parts of this application including the claims should be construed as widely as possible in view of the prior art.

Having thus described my invention what I claim is:-

1. An electrode for an aluminum furnace,

baked in the'furnace in which it is employed,

and comprising a lower baked portion and an upper unbaked portion and having an obling cross-section, the longest axis of which is in excess of forty-three inches and the shortest axis of which is approximately a maximum of fortythree inches.

2. An electrode assembly for an electric furnace, comprising in combination an electrode of oblong cross section having a lower baked portion and an upper unbaked portion and a metallic casing therefor, horizontal rows of contact studs independent of the casing and embedded in the two portions of the electrode, the studs of the several rows being in staggered formation, and means for connecting the corresponding studs of the horizontal and vertical rows in parallel.

3. An electric furnace electrode of oblong cross section, comprising a lower baked and an upper unbaked part, contact studs extending into the electrode from opposite sides thereof and arranged in horizontal rows, and an individual metal structure for each row of contact studs forming a frame surrounding the electrode, the metal .structure being of such design as to withstand not only the weight of the electrode and the contact studs acting vertically through the lower studs, but also the horizontal pressure from the fluid paste in the upper part of the electrode.

4. an electrode holder comprising in combination alternately stacked corresponding and interchangeable beams overlapping at their ends and adapted to surround the electrode, means for effecting supporting engagement between the electrode and at least two of the beams, suspending means for the beams interlocking the overlapped ends, means for removably attaching the suspending means to the beams successively from the lowest beams upward,

, holder approaches the melt in the furnace holder in suspending the 4 pending'means attached to the then lowest beams of the holder. I

5. An electrode holder for an electrode in which is embedded laterally projecti'ng studs comprising in combination alternately stacked corresponding and interchangeable beams overlapping attheir ends and adapted to surround the electrode in such relation of the beams are positioned beneath the studs and cooperate therewith in supporting the electrode, suspending means for the beams interlocking the overlapped ends, means for removably attaching the suspending means to the beams successively from the lowest beams upward, whereby as the electrode is burned off in use the lowest beams may be removed from the holder and similar beams added at the top as a part thereof and the suspending beams attached to the then low-' est beams of the holder.

6. An electrode'assembly for an electric furnace, comprising in combination an electrode of rectangular cross section baked in the furnace in which it is employed and having a lower baked portion and an upper unbaked portion, a metallic shell surrounding the electrode mass comprising the electrode, an electrode holder en-- circling the metallic shell and reenforcing the shell to prevent deformation of the velectrode from the hydrostatic pressure of the unbaked portion thereof, the said electrode holder being built up of a plurality of removable horizontal parts whereby the lowest parts may be removed as the and similar parts added to the upper part of the holderto continue its structure, and removable studs penetrating the electrode and projecting laterally therefrom and cooperating with the electrode. '7. An electrode assembly for an. electric fur- 40 nace, comprising in combination an electrode of thereto that at least two suspending the electrode rectangular cross section baked in the furnace in which it is employed and having a lower baked portion and an upper unbaked portion, a metallic shell surrounding the electrode mass comprising the electrode, an electrode holder encircling the metallic shell and reenforcing the shell to prevent deformation of the electrode from the hydrostatic pressure of' the unbaked portion thereof,-

the said electrode holder being built up of a plurality of removable horizontal parts whereby the lowest parts may be removed as the holder approaches the melt in the furnace and similar parts, added to the upper part-of the holder to continue its structure, removable studs penetrating the electrode and projecting laterally therefrom and cooperating with the holder in suspending the electrode, and auxiliary means for the lowest parts therefrom, said auxiliary means functioning through and in cooperation with the electrode holder itself.

- 8. In operating an electrode for an electric furnace which electrode is of oblong cross section, comprises a lower baked portion and an upper unbaked portion and is provided with horizontal rows of contact studs embedded in the two pertions of the electrode, the method which comprises suspending the electrode in'the furnace from the lowest row of studs in the baked portion of the electrode, supplying current to the electrode through these studs and through the studs of the row next above thereby completing the baking of the said row next above into the electrode, transferring the suspension of the electrode to the row of studs next higher up, removing the lowest studs, and in turn embedding another row of studs above in the unbaked portion of the electrode.

PIERRE TOR/CHET.

during the removal of 

